Chemiluminescent (CL) reactions suffer from low quantum yields because of completing dark reaction pathways; this can be overcome, if the excited state emitter can be stabilized. A monoclonal antibody raised against an appropriately designed target structure (one that closely resembles the excited state emitter) may serve as a surrogate binding molecule. The resultant enhanced CL can then be extremely useful in a variety of applications, e.g. immunoassays. The luminol peroxide reaction is one of the most widely utilized CL reactions. Antibodies raised against 3-aminophthalate (APA), the excited state emitter can be expected to enhance CL yield. In phase I efforts, several monoclonal antibodies to the APA hapten will be developed and their usefulness as CL enhancers will be examined. Additionally, anti- APA IgM secreting clones developed in earlier efforts will be manipulated to generate anti-APA IgG antibodies. The usefulness of all these antibodies will also be examined in the related isoluminol reaction. In Phase II studies, a larger bank of catalytic antibodies for these CL reactions as well as other reactions such as the acridinium ester reaction will be generated. The usefulness of all these catalytic antibodies in prototype immunoassays will also be examined, thus paving the way for commercial exploitation.